Process of making fire-polished sheet-glass.



PATENTED DEG. 15, 1903. H. G. SLINGLUFF. PROCESS OF MAKING "FIRE POLISHED SHEET GLASS.

APPLIGATION FILED SEPT. 12 1902. RENEWED MAY 13. 1903.-

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n4: ngmus PETERS co, PNOTO-LITHQ, WASH UNITED STATES Patented December 15, 1903.

PATENT OFFICE.

" HARRY e. sLINeLUFF, or HARTFORD oITY, INDIANA.

SPECIFICATION forming part of Letters Patent No. 747,335, dated December 15, 1903.

Original application filed March 25. 1902, Serial No. 99,916. Divided and this application filed $eptember 12, 1902. Renewed May 13,1903. Serial No. 157,025. (No model.)

and glass of maximum brilliancy produced without the use of the customary means for polishing the surface of the glass heretofore employed.

-In carrying out my improved fire-polishing process I prefer to apply it to sheet-glass which has been made by utilizing a stretching action, especially such as described and claimed in my application Serial No. 99,916, filed March 25, 1902, of which the present application is a division, because by that process the brilliant effect is secured, which has been heretofore derived from the use of ordinary polishing and rubbing devices, and hence the fire polishing materiallyincreases such effect; but it is to be understood that my fire-polishing process is not limited to glass formed by any particular process as it is applicable to all formed sheet-glass by whatever method produced.

In the drawings I have illustrated sufficient of the apparatus disclosed in my aforesaid application for forming the sheet of glass, and in connection therewith a suitable furnace and transferring device for transporting the glass from the forming apparatus to the said furnace, such as shown in my said pending application.

In the drawings, Figure 1 is a perspective View of an apparatus, with parts broken away, by which my process may be practiced; and Figs. 2 and 3 are detail views of the glasstransferring slings.

Referring now to the drawings I will first describe the forming apparatus with particular reference to Fig. 1, and in which drawings the same reference characters relate to per end engagingpins on the side plates, and

at its lower end are curved rack-bars 12, held in straps 14E by locking-pins 13. Each table is pr eferably provided with a chamber or passage 7, through which water is constantly circulated by means of the pipes 8 for the table 3 and 9 for the table 1, flexible sections 10 being inserted in the pipes 8 to permit the movement of the table 3 on its pivot and all of said pipes being connected with a suitable source of water-supply, not shown. The table 1 rests upon the side frames and the upper cross-bars andis provided with a curved rack-bar 12*, which may be adjusted and held in different positions by the locking-pin 13 passing through the strap 14, secured to the fixed side frames. The table 3 is made similarly adjustable, as above described, or any other suitable adjusting means may be employed for this purpose on each table. Attached to the sides of the table 3 are guides bars 15, which project an equal distance on each side of the table, such distance being determined by the thickness of the sheet of glass to be made, as indicated by the numeral 4. These guide-bars are preferably adjustable to provide for sheets of diiferent thicknesses, and for this purpose I have shown slots 16, in which are countersunk bolts 17 The guide-bars may be released by unscrewing the confining-nuts on the bolts, and after shifting the guide-bars to the desired position the nuts are again tightened to fix said bars in place. Slidably mounted on the guidebars is a presser 17, carried by slides 21, embracing and movably mounted on said bars 15. The presser is connected by a link to a lever 19, fulcru med at to standards 24, fixed to the frame of the machine. This lever 19 is normally held up by any suitable means,

such as a coil-spring 26, having one end fixed,

to the lever and the other end to one of the standards 24 or any other fixed part of the machine. Below the presser 17 is a traveler 18, here shown in the form of a shallow trough, which is lined with graphite to prevent the glass from adhering thereto. This traveler is carried by slides 21, slidably mounted upon guide-bars 15, each of which slides is provided with an ear or lug 26", through which loosely passes a rod 22, provided with screwthreaded ends upon which are mounted confining-nuts 20 20*. These nuts hold the presser and travelera predetermined distance apart,which distance may be varied by proper adjustment of either of the nuts.

The apparatus thus described is adapted for the production of glass sheets by the process described and claimed in my aforesaid application and as hereinafter briefly described, and after the sheet is formed it must be transferred to a suitable fire-polishing furnace, in which manipulation the principal feature of my present invention resides.

I prefer to provide in connection with the press a shifting-crane ofthe form shown for transferring the sheet of glass from the table to a furnace 37. This crane consists of the usual post 27, carrying a swinging arm 28, upon the top of which is mounted a traveling rod 29, suitably confined by rollers 30 to the swinging arm, and upon this arm is preferably fixedly mounted an asbestos sling,which receives the sheet of glass at from the table, as shown in Fig. 1. By swinging the arm 28 from the table in line with the opening in the furnace when the press is located near the same and pushing the rod 29 the sheet of glass is conveyed to the furnace, where it is subjected to a proper degree of heat for firepolishing and annealing. 'These asbestos slings in the instance shown are made of a bottom plate 31, from which rise two fixed arms 33 and two pivoted arms 32, the latter being adapted to be lowered, in the position shown in Figs. 1 and 3, to receive the sheet of glass, after which they are closed, as shown in Fig. 2, and clamped togetherby the clamping-screw 36. At the upper ends of each of the arms is a pivoted clamping-jaw 34,through a slot in the lower end of which passes pins having asbestos contact-points 35, adapted to press against the sides of the glass and hold the same in upright position and prevent sagging while the sheet is being transferred to and remains in the furnace. The weight of the glass upon the bottom of the slings, it will be observed, tends to press the asbestos con tact-points into contact with the sheet and maintain the same in proper position. The glass sheet is therefore not only suspended or held at the top with its sides free from contact, except at a limited area of contact near the top thereof, with any substance which would otherwise destroy or mar the surface, brilliancy, and polish of the sides, but the support afiorded by the base of the slings is sufiicient to prevent the possible thinning of the sheet by its own weight while undergoing the fire-polishing step.

' With this brief description of the apparatus shown I will now describe the manner of forming the sheet and carrying out the firepolishing process. The batch of glass is conveyed, by means of an ordinary ladle of sulficient capacity to hold the amount required, for a sheet from the melting furnace or pot to the table and placed thereon, whereupon a T-iron is pressed against one side of the batch, the molten glass adhering thereto, in which position the traveler 18 is just below the table 1. The T-iron is then pushed forward, carrying with it the batch of glass,

-which flows over the edge of the table 1 and rests in the traveler 18. The T-iron after being pushed as close to the edge of the table as possible is drawn back a sufficient distance to permit the cut-off plate 23 to be swung into position, thereby cutting off the batch of glass from the T-iron, to which a small strip adheres. This movement of the cut-ofi? plate not only severs the batch from the T-iron, but clamps or binds a small stratum at the upper edge of the batch between the upper edge of the table 3 and the bottom of the said swinging plate, so that the glass is held by pressure at this point. The distance between the lower part of the cut-off plate, which preferably coincides with the bottom of the table 1 and the upper edge of the table 3, is made equal to the desired thickness of the sheet to be madethat is, this distance will equal the extension or projection 4 of the guide-bars beyond the fiat surface of the table 3. With the glass held in this position the operator grasps the lever 19, forcing it downward, the weight of the glass batch in the traveler causing the latter to precede the advancing presser or plunger 17, the latter of which is guided by the guide-bars 15. By this action the glass is caused to flow by its own weight downwardly over the flat surface of the table 3 and is thereby stretched in advance of the pressing action. While in this stretched condition the plunger or presser l7 smooths the surface of the glass and presses the same against the fiat surface of the vertical table 3, producing a sheet of glass of the desired thickness, such presser continu ing its downward movementuntil the whole sheet has been stretched and pressed into the desired form. The rod 22 contacting with the floor stops the traveler at its lowest point and permits the presser to approach the traveler may be adjusted at an angle to the vertical by means of the rack-bars 12 and lockingpins 13, as hereinbefore indicated. After the glass has been pressed into shape, as above I described, the lever 19 is raised to its upperheat.

most position, carrying with it the plunger and traveler, the cut off plate is thrown back, and the sheet may be removed and fiattened by any of theusual flattening means, if desired. In order to impart a polish to the formed sheet of glass, it is subjected to a high heat in any suitable furnace, one conventionallyshown at 37 in the drawings,to accomplish which result the sheet of glass is transferred to the asbestos sling 31 on the traveling rod 29, carried by the crane, and this rod swung into position in front of the furnace and the sheet conveyed thereinto,ashereinbeforeindicated. The heat of the furnace will depend upon the quality of the glass, care being takenthat it is not high enough to melt the glass; but I may saythat the heat necessary to the polishing approximates 1600. This heat may vary considerably, according to different qualities of glass and the length of time for which the glass remains in the furnace. The

success of this process depends upon the,

length of time the sheet is permitted to remain in the furnace and the intensity of the For example, a thin sheet cannot remain in the furnace as long as a thicker heavier sheet, and I may add that the higher the heat that can be maintained the better will be the polishing effect and the quicker will the said polishing efiect be attained, and I have found that under the best conditions a sheet of glass can be polished in one minute or less.

In some cases with glass sheets produced by my stretching process it sometimes happens that the surface is blurred slightly and the fire-polishing quickly restores this brilliancy of the glass so blurred and materially assists in annealing the sheet. Furthermore,

glass made in other ways, such as by rolling, where the brilliancy of surface has been lost, can have this surface brilliancy restored by the fire-polishing process herein described.

I claim as my invention- 1. In the art of making sheet-glass, the herein-described process of forming and imparting surface brilliancy to a sheet of glass which consists in forming the sheet transferring the formed sheet of glass while supported in a vertical position; at the top and bottom with its sides free from contact with any substance except at a limited area of contact near the top thereof, and then subjecting the sheet while so supported to the action of a high heat to impart a fire polish thereto, substantially as described.

2. As an improvement in the art of making sheet-glass, the process of forming and polishing a sheet of glass which consists in cansing a molten mass of glass to flow downwardly by its own weight over aflat surface, following said action, by pressing the sheet against the said surface, and subjecting the sheet thus formed to a heat of sufficient temperature to impart a fire polish thereto, substantially as described.

3. In the art of making sheet-glass, the herein-described process of forming a sheet of glass from a molten mass of glass by the combined action of first suspending the molten mass from its top and causing the glass to flow downwardly against a flat surface and stretch 'by its own weight into sheet form, then pressing the glass smooth and finally subjecting the sheet so formed to a high heat, substantially-as described.

4. In the art of making sheet-glass, the herein-described process of forming a sheet of glass from a molten massof glass by the combined action of first suspending the molten mass from its top and causing the glass to flow downwardly by its own weight against a fiat surface and stretch by its weight into sheet form, then transferring said formed sheet while suspended in a vertical position with its sides free from contact with any substance except at a limited area of contact near the top thereof and then subjecting it toga high heat while so supported ,to impart a fire polish thereto, substantially as described.

In testimony whereof I have signed my I name to this specification in the presence of Witnesses:

H. O. DAVISSON, E. O. OHAFFEE. 

